Here's a breakdown:

* DNA (Deoxyribonucleic Acid): The molecule that carries the genetic instructions for building and maintaining an organism. It's like a blueprint for life.

* Genes: Specific segments of DNA that contain the instructions for building a particular protein or RNA molecule. These proteins and RNA molecules are responsible for carrying out various functions in the body, ultimately contributing to the organism's traits.

* Traits: Observable characteristics of an organism, such as eye color, height, or susceptibility to certain diseases.

So, genes are the functional units of heredity, and they determine the traits an organism inherits.